When disabling transparent huge pages on server start up via /etc/rc.local warnings about THP being enabled are presented when starting the mongo shell and in the mongodb.log.

Because commands in rc.local are executed at the end of the multiuser run level which mongodb starts the mongo server reports that transparent huge pages are still enabled even though they had been disabled.

$ tail /var/log/mongodb/mongodb.log

• • • • • SERVER RESTARTED *****
          ...
          2015-02-27T13:32:22.946-0800 I CONTROL [initandlisten] ** WARNING: /sys/kernel/mm/transparent_hugepage/enabled is 'always'.
          2015-02-27T13:32:22.946-0800 I CONTROL [initandlisten] ** We suggest setting it to 'never'
          2015-02-27T13:32:22.946-0800 I CONTROL [initandlisten]
          2015-02-27T13:32:22.946-0800 I CONTROL [initandlisten] ** WARNING: /sys/kernel/mm/transparent_hugepage/defrag is 'always'.
          2015-02-27T13:32:22.946-0800 I CONTROL [initandlisten] ** We suggest setting it to 'never'

$ cat /sys/kernel/mm/transparent_hugepage/enabled
always madvise [never]